Dirt detection system, lidar unit, sensing system for vehicle, and vehicle

ABSTRACT

This dirt detection system is composed to detect dirt attached to an outer cover of a lighting tool for a vehicle. A camera, a LiDAR unit, and a millimeter wave radar, which detect the surrounding environment of the vehicle, are each mounted on the lighting tool for a vehicle. The dirt detection system is provided with: a thermal imaging camera composed to acquire thermal image data showing the outer cover; a lighting tool cleaner composed to remove the dirt attached to the outer cover; and a lighting tool cleaner control unit composed to determine, on the basis of the thermal image data, whether the dirt is attached to the outer cover and to drive the lighting tool cleaner in response to the determination that the dirt is attached to the outer cover.

TECHNICAL FIELD

The present disclosure relates to a dirt detection system, a LiDAR unit, a sensing system for a vehicle, and a vehicle. In particular, the present disclosure relates to a dirt detection system and a sensing system for a vehicle for detecting dirt on an outer cover of a vehicle lamp provided in a vehicle.

BACKGROUND ART

Currently, research on automatic driving techniques of automobiles has been actively conducted in various countries, and each country considers legislation to allow a vehicle (hereinafter, the “vehicle” refers to an “automobile”) to travel on public roads in an automatic driving mode. Here, in the automatic driving mode, a vehicle system automatically controls traveling of the vehicle. Specifically, in the automatic driving mode, the vehicle system automatically performs at least one of steering control (control on an advancing direction of the vehicle), brake control, and accelerator control (control on braking, and acceleration or deceleration of the vehicle) based on information indicating a surrounding environment of the vehicle (surrounding environment information) acquired from a sensor such as a camera or a radar (for example, a laser radar or a millimeter wave radar). On the other hand, in a manual driving mode to be described below, a driver controls traveling of the vehicle, as is often the case of many related-art vehicles. Specifically, in the manual driving mode, the traveling of the vehicle is controlled according to an operation (a steering operation, a brake operation, and an accelerator operation) of the driver, and the vehicle system does not automatically perform the steering control, the brake control, and the accelerator control. A vehicle driving mode is not a concept that exists only in a part of vehicles, but a concept that exists in all vehicles including the related-art vehicles that do not have an automatic driving function, and the vehicle driving mode is classified according to, for example, a vehicle control method.

Therefore, it is expected that a vehicle traveling in the automatic driving mode (hereinafter, appropriately referred to as “automatic driving vehicle”) and a vehicle that travels in the manual driving mode (hereinafter, appropriately referred to as “manual driving vehicle”) coexist on the public road in the future.

As an example of the automatic driving technique, Patent Literature 1 discloses an automatic following travel system for a following vehicle to automatically follow a preceding vehicle. In the automatic following travel system, each of the preceding vehicle and the following vehicle includes an illumination system. Character information for preventing other vehicles from cutting in between the preceding vehicle and the following vehicle is displayed on the illumination system of the preceding vehicle, and character information indicating that the following vehicle automatically follows the preceding vehicle is displayed on the illumination system of the following vehicle.

Patent Literature 1: JP H09-277887 A

SUMMARY OF INVENTION

In the development of the automatic driving technique, it is necessary to dramatically increase detection accuracy of a surrounding environment of the vehicle. In this regard, mounting a plurality of different types of sensors (for example, a camera, a LiDAR unit, a millimeter wave radar, and the like) on a vehicle is currently being considered. For example, it is considered to provide a plurality of sensors at each of four corners of the vehicle. Specifically, it is considered to mount a LiDAR unit, a camera, and a millimeter wave radar on each of four vehicle lamps provided at the four corners of the vehicle.

The LiDAR unit disposed in the vehicle lamp acquires point group data indicating the surrounding environment of the vehicle through a transparent outer cover. Similarly, the camera provided in the vehicle lamp acquires image data indicating the surrounding environment of the vehicle through the transparent outer cover. Therefore, when dirt adheres to the outer cover of the vehicle lamp, there is a risk that the surrounding environment of the vehicle cannot be accurately specified based on the point group data of the LiDAR unit and/or the image data of the camera due to the dirt (mud, dust, or the like) adhering to the outer cover. As described above, when a sensor such as the LiDAR unit or the camera is provided in the vehicle lamp, it is necessary to consider a method for detecting dirt that adheres to the outer cover and adversely affects the detection accuracy of the sensor.

An object of the present disclosure is to provide a system capable of suppressing a decrease in detection accuracy of a sensor disposed in a vehicle lamp.

According to an aspect of the present disclosure, there is provided a dirt detection system configured to detect dirt adhering to an outer cover of a vehicle lamp. A sensor that detects a surrounding environment of a vehicle is mounted on the vehicle lamp. The dirt detection system includes: a thermal imaging camera configured to acquire thermal image data indicating the outer cover; a lamp cleaner configured to remove dirt adhering to the outer cover; and a lamp cleaner control unit configured to determine based on the thermal image data whether there is dirt adhering to the outer cover, and to drive the lamp cleaner in response to a determination that there is dirt adhering to the outer cover.

According to the above configuration, it is determined based on the thermal image data whether there is dirt adhering to the outer cover, and further the lamp cleaner is driven in response to the determination that there is dirt adhering to the outer cover. In this way, dirt adhering to the outer cover can be detected based on the thermal image data acquired from the thermal imaging camera. In this regard, since dirt such as mud absorbs light emitted from an illumination unit or light emitted from a LiDAR unit, a temperature of the dirt is higher than a temperature of the outer cover. Therefore, it is possible to detect dirt adhering to the outer cover based on the thermal image data.

Therefore, since it is possible to reliably detect dirt adhering to the outer cover, it is possible to suppress a decrease in detection accuracy of a sensor (in particular, a LiDAR unit, a camera, or the like) disposed in a space defined by the outer cover and a housing of the vehicle lamp.

The thermal imaging camera may be disposed in a space defined by a housing and the outer cover of the vehicle lamp.

According to the above configuration, since the thermal imaging camera is disposed in the space defined by the housing and the outer cover of the vehicle lamp, it is possible to reliably determine whether there is dirt adhering to the outer cover based on the thermal image data indicating the outer cover.

The lamp cleaner control unit may be configured to determine based on the thermal image data whether there is dirt adhering to the outer cover when there is no pedestrian present within a predetermined range from the vehicle.

According to the above configuration, since the above determination processing is executed when there is no pedestrian present within the predetermined range from the vehicle, it is possible to reliably prevent a situation where a pedestrian is indicated in the thermal image data. In this way, it is possible to reliably prevent a situation (that is, erroneous detection of dirt) where a pedestrian that radiates heat is determined as dirt adhering to the outer cover.

The lamp cleaner control unit may be configured to specify a high-temperature region having a temperature equal to or higher than a threshold temperature based on the thermal image data, determine whether the specified high-temperature region covers an area equal to or larger than a predetermined area, and determine that there is dirt adhering to the outer cover when the high-temperature region covers an area equal to or larger than the predetermined area.

According to the above configuration, it is possible to reliably determine whether there is dirt adhering to the outer cover based on the thermal image data indicating the outer cover.

The lamp cleaner control unit may be configured to determine the threshold temperature according to an outside air temperature outside the vehicle.

According to the above configuration, since the threshold temperature is determined according to the outside air temperature, it is possible to execute optimum dirt determination processing in accordance with the outside air temperature. That is, it is possible to reliably prevent a situation where dirt adhering to the outer cover is not detected in accordance with the outside air temperature.

A vehicle including the dirt detection system may be provided.

According to the above, it is possible to provide a vehicle capable of suppressing a decrease in detection accuracy of a sensor disposed in a vehicle lamp.

According to another aspect of the present disclosure, there is provided a LiDAR unit that includes: a first light emitting unit configured to emit first laser light having a first peak wavelength; a first light receiving unit configured to receive reflected light of the first laser light and to photoelectrically convert the reflected light of the first laser light; a second light emitting unit configured to emit second laser light having a second peak wavelength different from the first peak wavelength; a second light receiving unit configured to receive reflected light of the second laser light and to photoelectrically convert the reflected light of the second laser light; a first generation unit configured to generate first point group data based on an emission time of the first laser light and a light reception time of the reflected light of the first laser light; and a second generation unit configured to generate second point group data based on an emission time of the second laser light and a light reception time of the reflected light of the second laser light. A detection wavelength range of the first light receiving unit and a detection wavelength range of the second light receiving unit do not overlap each other.

According to the above configuration, the LiDAR unit can generate the first point group data associated with the first laser light and the second point group data associated with the second laser light. In this way, it is possible to provide a LiDAR unit capable of acquiring two different sets of point group data. For example, it is possible to specify a surrounding environment of the vehicle, on which the LiDAR unit is mounted, by using one set of point group data (for example, the first point group data) of the two sets of point group data. Further, it is possible to specify information other than that of the surrounding environment of the vehicle (for example, information on dirt adhering to the outer cover) by using the other set of point group data (for example, the second point group data) of the two sets of point group data.

An emission intensity of the second laser light may be smaller than an emission intensity of the first laser light.

According to the above configuration, since the emission intensity of the second laser light is smaller than the emission intensity of the first laser light, it is possible to make a surrounding environment indicated by the first point group data and a surrounding environment indicated by the second point group data different from each other. For example, it is possible to acquire information on dirt adhering to the outer cover by using the second point group data while acquiring surrounding environment information on an outside of the vehicle by using the first point group data.

According to another aspect of the present disclosure, there is provided a sensing system for a vehicle configured to detect dirt adhering to an outer cover of a vehicle lamp provided in a vehicle. The sensing system for a vehicle includes: the LiDAR unit disposed in a space defined by a housing and the outer cover of the vehicle lamp, and configured to acquire first point group data and second point group data indicating a surrounding environment outside the vehicle; a lamp cleaner configured to remove dirt adhering to the outer cover; and a lamp cleaner control unit configured to determine whether there is dirt adhering to the outer cover based on the second point group data, and to drive the lamp cleaner in response to a determination that there is dirt adhering to the outer cover.

According to the above configuration, it is determined based on the second point group data whether there is dirt adhering to the outer cover, and further the lamp cleaner is driven in response to the determination that there is dirt adhering to the outer cover. Thus, it is possible to detect the dirt adhering to the outer cover based on the second point group data of one of the two sets of point group data acquired from the LiDAR unit. In this regard, when dirt such as rain, snow, or mud adheres to the outer cover, a point group indicating the dirt adhering to the outer cover appears in the second point group data, and thus it is possible to detect dirt adhering to the outer cover based on the point group. Accordingly, since it is possible to reliably detect the dirt adhering to the outer cover, it is possible to suppress a decrease in detection accuracy of a sensor such as the LiDAR unit disposed in the vehicle lamp.

The second point group data may indicate a surrounding environment within a predetermined distance from the LiDAR unit. When there is dirt adhering to the outer cover, the lamp cleaner control unit may determine, as dirt adhering to the outer cover, a point group indicated by the second point group data.

According to the above configuration, the point group indicated by the second point group data is determined as dirt adhering to the outer cover. In this way, since a point group indicating an object existing outside the vehicle does not appear in the second point group data, it is possible to determine whether there is dirt adhering to the outer cover based on presence or absence of a point group appearing in the second point group data.

The second point group data may indicate a surrounding environment outside the vehicle. When there is dirt adhering to the outer cover, the lamp cleaner control unit may determine, as dirt adhering to the outer cover, a point group that is indicated by the second point group data and that exists within a predetermined distance from the LiDAR unit.

According to the above configuration, the point group indicated by the second point group data and existing within the predetermined distance from the LiDAR unit is determined as dirt adhering to the outer cover. In this way, even when the second point group data indicates the surrounding environment outside the vehicle, it is possible to determine whether there is dirt adhering to the outer cover based on presence or absence of a point group indicated within the predetermined distance.

A vehicle including the sensing system for a vehicle is provided.

According to the above, it is possible to provide a vehicle capable of suppressing a decrease in detection accuracy of a sensor disposed in a vehicle lamp.

According to the present disclosure, it is possible to provide a system capable of suppressing a decrease in detection accuracy of a sensor disposed in a vehicle lamp.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a vehicle including a vehicle system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating the vehicle system according to the first embodiment.

FIG. 3A is a block diagram illustrating a left-front sensing system.

FIG. 3B is a block diagram illustrating a left-front dirt detection system.

FIG. 4 is a flowchart for illustrating a method of detecting dirt adhering to an outer cover.

FIG. 5 is a schematic diagram of a vehicle including a vehicle system according to a second embodiment.

FIG. 6 is a block diagram illustrating the vehicle system according to the second embodiment.

FIG. 7 is a block diagram illustrating a left-front sensing system.

FIG. 8 is a block diagram illustrating a configuration of a LiDAR unit according to the second embodiment.

FIG. 9 is a schematic diagram of the LiDAR unit according to the second embodiment.

FIG. 10 is a flowchart for illustrating a method of detecting dirt adhering to an outer cover according to the second embodiment.

FIG. 11 is a diagram illustrating first laser light and second laser light emitted from a LiDAR unit.

DESCRIPTION OF EMBODIMENTS First Embodiment

Hereinafter, a first embodiment of the present disclosure (hereinafter, simply referred to as “the present embodiment”) will be described with reference to the drawings. A description of members having the same reference numerals as members that have been described in the description of the present embodiment will be omitted for convenience of description. Dimensions of members shown in the drawings may be different from actual dimensions of the members for convenience of description.

Further, in the description of the present embodiment, for convenience of description, a “left-right direction”, a “front-rear direction”, and an “up-down direction” may be referred to as appropriate. These directions are relative directions set for a vehicle 1 illustrated in FIG. 1. Here, the “front-rear direction” is a direction including a “front direction” and a “rear direction”. The “left-right direction” is a direction including a “left direction” and a “right direction”. The “up-down direction” is a direction including an “upward direction” and a “downward direction”. Although the up-down direction is not shown in FIG. 1, the up-down direction is a direction perpendicular to the front-rear direction and the left-right direction.

First, the vehicle 1 and a vehicle system 2 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram illustrating a top view of the vehicle 1 that includes the vehicle system 2. FIG. 2 is a block diagram illustrating the vehicle system 2.

The vehicle 1 is a vehicle (automobile) that can travel in an automatic driving mode, and as illustrated in FIG. 1, includes the vehicle system 2, a left-front lamp 7 a, a right-front lamp 7 b, a left-rear lamp 7 c, and a right-rear lamp 7 d.

As illustrated in FIGS. 1 and 2, the vehicle system 2 includes at least a vehicle control unit 3, a left-front sensing system 4 a (hereinafter, simply referred to as a “sensing system 4 a”), a right-front sensing system 4 b (hereinafter, simply referred to as a “sensing system 4 b”), a left-rear sensing system 4 c (hereinafter, simply referred to as a “sensing system 4 c”), and a right-rear sensing system 4 d (hereinafter, simply referred to as a “sensing system 4 d”).

The vehicle system 2 further includes a left-front dirt detection system 6 a (hereinafter, simply referred to as a “dirt detection system 6 a”), a right-front dirt detection system 6 b (hereinafter, simply referred to as a “dirt detection system 6 b”), a left-rear dirt detection system 6 c (hereinafter, simply referred to as a “dirt detection system 6 c”), and a right-rear dirt detection system 6 d (hereinafter, simply referred to as a “dirt detection system 6 d”).

The vehicle system 2 further includes a sensor 5, a human machine interface (HMI) 8, a global positioning system (GPS) 9, a wireless communication unit 10, and a storage device 11. In addition, the vehicle system 2 includes a steering actuator 12, a steering device 13, a brake actuator 14, a brake device 15, an accelerator actuator 16, and an accelerator device 17.

The vehicle control unit 3 is configured to control traveling of the vehicle 1. The vehicle control unit 3, for example, is configured with at least one electronic control unit (ECU). The electronic control unit includes a computer system (for example, a system on a chip (SoC)) including one or more processors and one or more memories; and an electronic circuit including an active element such as a transistor and a passive element. The processor includes, for example, at least one of a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU) and a tensor processing unit (TPU). The CPU may be configured with a plurality of CPU cores. The GPU may be configured with a plurality of GPU cores. The memory includes a read only memory (ROM) and a random access memory (RAM). The ROM may store a vehicle control program. For example, the vehicle control program may include an artificial intelligence (AI) program for automatic driving. The AI program is a program (a trained model) constructed by supervised or unsupervised machine learning (in particular, deep learning) using a multilayer neural network. The RAM may temporarily store a vehicle control program, vehicle control data, and/or surrounding environment information indicating a surrounding environment of the vehicle. The processor may be configured to load a program designated from various vehicle control programs stored in the ROM onto the RAM and execute various types of processing in cooperation with the RAM. Further, the computer system may be configured with a non-von Neumann computer such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). Furthermore, the computer system may be configured with a combination of a Von Neumann computer and a non-Von Neumann computer.

Each of the sensing systems 4 a to 4 d is configured to detect a surrounding environment of the vehicle 1. In the description of the present embodiment, it is assumed that the sensing systems 4 a to 4 d include the same components. Therefore, the sensing system 4 a will be described below with reference to FIG. 3A. FIG. 3A is a block diagram illustrating the sensing system 4 a.

As illustrated in FIG. 3A, the sensing system 4 a includes a control unit 40 a, an illumination unit 42 a, a camera 43 a, a light detection and ranging (LiDAR) unit 44 a (an example of a laser radar), and a millimeter wave radar 45 a. The control unit 40 a, the illumination unit 42 a, the camera 43 a, the LiDAR unit 44 a, and the millimeter wave radar 45 a are provided in a space Sa defined by a housing 24 a of the left-front lamp 7 a and a translucent outer cover 22 a that are illustrated in FIG. 1. Alternatively, the control unit 40 a may be disposed at a predetermined portion of the vehicle 1 other than the space Sa. For example, the control unit 40 a may be configured integrally with the vehicle control unit 3.

The control unit 40 a is configured to control operations of the illumination unit 42 a, the camera 43 a, the LiDAR unit 44 a, and the millimeter wave radar 45 a. In this regard, the control unit 40 a functions as an illumination unit control unit 420 a, a camera control unit 430 a, a LiDAR unit control unit 440 a, and a millimeter wave radar control unit 450 a. The control unit 40 a is configured with at least one electronic control unit (ECU). The electronic control unit includes a computer system (for example, a SoC) including one or more processors and one or more memories, and an electronic circuit including an active element such as a transistor and a passive element. The processor includes at least one of a CPU, an MPU, a GPU and a TPU. The memory includes a ROM and a RAM. Further, the computer system may be configured with a non-von Neumann computer such as an ASIC or an FPGA.

The illumination unit 42 a is configured to emit light toward an outside (a front side) of the vehicle 1 to form a light distribution pattern. The illumination unit 42 a includes a light source that emits light and an optical system. The light source may be configured with, for example, a plurality of light emitting elements arranged in a matrix (for example, N rows×M columns, N>1 and M>1). The light emitting element is, for example, a light emitting diode (LED), a laser diode (LD), or an organic EL element. The optical system may include at least one of a reflector configured to reflect light emitted from the light source toward a front side of the illumination unit 42 a, and a lens configured to refract light directly emitted from the light source or light reflected by the reflector.

The illumination unit control unit 420 a is configured to control the illumination unit 42 a such that the illumination unit 42 a emits light of a predetermined light distribution pattern toward a front region of the vehicle 1. For example, the illumination unit control unit 420 a may change the light distribution pattern of light emitted from the illumination unit 42 a according to a driving mode of the vehicle 1.

The camera 43 a is configured to detect a surrounding environment of the vehicle 1. In particular, the camera 43 a is configured to acquire image data indicating the surrounding environment of the vehicle 1 and then transmit the image data to the camera control unit 430 a. The camera control unit 430 a may specify surrounding environment information based on the transmitted image data. Here, the surrounding environment information may include information on an object that exists outside the vehicle 1. For example, the surrounding environment information may include information on an attribute of the object existing outside the vehicle 1 and information on a distance, a direction and/or a position of the object with respect to the vehicle 1. The camera 43 a includes, for example, an imaging element such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The camera 43 a may be configured as a monocular camera or a stereo camera. When the camera 43 a is a stereo camera, the control unit 40 a can specify, by using the parallax, a distance between the vehicle 1 and an object (for example, a pedestrian) existing outside the vehicle 1 based on two or more pieces of image data acquired by the stereo camera.

The LiDAR unit 44 a is configured to detect a surrounding environment of the vehicle 1. In particular, the LiDAR unit 44 a is configured to acquire point group data indicating the surrounding environment of the vehicle 1 and then transmit the point group data to the LiDAR unit control unit 440 a. The LiDAR unit control unit 440 a may specify surrounding environment information based on the transmitted point group data.

More specifically, the LiDAR unit 44 a acquires information on a time of flight (TOF) ΔT1 of laser light (light pulse) at each emission angle (a horizontal angle θ and a vertical angle φ) of the laser light. The LiDAR unit 44 a can acquire information on a distance D between the LiDAR unit 44 a and an object existing outside the vehicle 1 at each emission angle, based on the information on the time of flight ΔT1 at each emission angle.

The LiDAR unit 44 a includes, for example, a light emitting unit configured to emit laser light, an optical deflector configured to perform scanning with the laser light in a horizontal direction and a vertical direction, an optical system such as a lens, and a light receiving unit configured to receive the laser light reflected by an object. A peak wavelength of the laser light emitted from the light emitting unit is not particularly limited. For example, the laser light may be invisible light (infrared light) having a peak wavelength of about 900 nm. The light emitting unit is, for example, a laser diode. The optical deflector is, for example, a micro electro mechanical systems (MEMS) mirror or a polygon mirror. The light receiving unit is, for example, a photodiode. The LiDAR unit 44 a may acquire the point group data, without the optical deflector performing scanning with the laser light. For example, the LiDAR unit 44 a may acquire the point group data by using a phased array method or a flash method. In addition, the LiDAR unit 44 a may acquire the point group data by mechanically driving and rotating the light emitting unit and the light receiving unit.

The millimeter wave radar 45 a is configured to detect radar data indicating a surrounding environment of the vehicle 1. In particular, the millimeter wave radar 45 a is configured to acquire radar data and then transmit the radar data to the millimeter wave radar control unit 450 a. The millimeter wave radar control unit 450 a is configured to acquire surrounding environment information based on the radar data. The surrounding environment information may include information on an object existing outside the vehicle 1. For example, the surrounding environment information may include information on a position and a direction of the object with respect to the vehicle 1 and information on a relative speed of the object with respect to the vehicle 1.

For example, the millimeter wave radar 45 a can acquire a distance between the millimeter wave radar 45 a and the object existing outside the vehicle 1 and a direction using a pulse modulation method, a frequency modulated continuous wave (FM-CW) method, or a two-frequency CW method. When the pulse modulation method is used, the millimeter wave radar 45 a can acquire information on a time of flight ΔT2 of a millimeter wave, and then acquire information on a distance D between the millimeter wave radar 45 a and the object existing outside the vehicle 1 based on the information on the time of flight ΔT2. In addition, the millimeter wave radar 45 a can acquire information on the direction of the object with respect to the vehicle 1 based on a phase difference between a phase of the millimeter wave (received wave) received by one reception antenna and a phase of the millimeter wave (received wave) received by another reception antenna adjacent to the one reception antenna. Further, the millimeter wave radar 45 a can acquire information on a relative speed V of the object with respect to the millimeter wave radar 45 a based on a frequency f0 of a transmitted wave emitted from a transmission antenna and a frequency f1 of a received wave received by a reception antenna.

Similarly, each of the sensing systems 4 b to 4 d includes a control unit, an illumination unit, a camera, a LiDAR unit, and a millimeter wave radar. In particular, these devices of the sensing system 4 b are disposed in a space Sb defined by a housing 24 b of the right-front lamp 7 b and a translucent outer cover 22 b that are illustrated in FIG. 1. These devices of the sensing system 4 c are disposed in a space Sc defined by a housing 24 c of the left-rear lamp 7 c and a translucent outer cover 22 c. These devices of the sensing system 4 d are disposed in a space Sd defined by a housing 24 d of the right-rear lamp 7 d and a translucent outer cover 22 d.

Next, the dirt detection systems 6 a to 6 d will be described. Each of the dirt detection systems 6 a to 6 d is configured to detect dirt (for example, mud and dust) adhering to the outer cover and remove the detected dirt. In this regard, the dirt detection system 6 a is configured to detect dirt adhering to the outer cover 22 a and remove the dirt. Similarly, the dirt detection system 6 b is configured to detect dirt adhering to the outer cover 22 b and remove the dirt. The dirt detection system 6 c is configured to detect dirt adhering to the outer cover 22 c and remove the dirt. The dirt detection system 6 d is configured to detect dirt adhering to the outer cover 22 d and remove the dirt.

It is assumed that the dirt detection systems 6 a to 6 d include the same components. Therefore, hereinafter, the dirt detection system 6 a will be described with reference to FIG. 3B. FIG. 3B is a block diagram illustrating the dirt detection system 6 a.

As illustrated in FIG. 3B, the dirt detection system 6 a includes a thermal imaging camera 62 a, a lamp cleaner 63 a, and a lamp cleaner control unit 64 a. The thermal imaging camera 62 a is, for example, a thermo viewer, and is configured to acquire thermal image data. The thermal image data captured by the thermal imaging camera 62 a makes it possible to visualize an object existing around the thermal imaging camera 62 a that generates heat (in particular, an object that emits infrared rays). The thermal imaging camera 62 a includes an imaging element having light receiving sensitivity to infrared rays (particularly, far infrared rays).

The thermal imaging camera 62 a is disposed in the space Sa (see FIG. 1), and is configured to acquire thermal image data indicating the outer cover 22 a. In particular, the thermal imaging camera 62 a may be disposed in the vicinity of the LiDAR unit 44 a disposed in the space Sa. Further, the thermal imaging camera 62 a may be configured to image a region of the outer cover 22 a through which the laser light emitted from the LiDAR unit 44 a passes. In the present embodiment, the thermal imaging camera 62 a is configured to detect dirt adhering to the outer cover 22 a, and may be configured to detect an object existing around the vehicle 1 that radiates heat, such as a pedestrian. As described above, the vehicle control unit 3 may determine an attribute of an object existing around the vehicle 1 as a person based on the thermal image data transmitted from the thermal imaging camera 62 a.

The lamp cleaner 63 a is configured to remove dirt adhering to the outer cover 22 a, and is disposed in the vicinity of the outer cover 22 a. The lamp cleaner 63 a may be configured to remove dirt adhering to the outer cover 22 a by injecting a cleaning liquid or air toward the outer cover 22 a.

The lamp cleaner control unit 64 a is configured to control the thermal imaging camera 62 a and the lamp cleaner 63 a. The lamp cleaner control unit 64 a is configured to receive thermal image data from the thermal imaging camera 62 a, and determine whether there is dirt adhering to the outer cover 22 a based on the received thermal image data. Further, the lamp cleaner control unit 64 a is configured to drive the lamp cleaner 63 a in response to a determination that there is dirt adhering to the outer cover 22 a.

The lamp cleaner control unit 64 a is configured with at least one electronic control unit (ECU). The electronic control unit includes a computer system (for example, a SoC) including one or more processors and one or more memories, and an electronic circuit including an active element such as a transistor and a passive element. The processor includes at least one of a CPU, an MPU, a GPU and a TPU. The memory includes a ROM and a RAM. Further, the computer system may be configured with a non-von Neumann computer such as an ASIC or an FPGA.

Returning to FIG. 2, the sensor 5 may include an acceleration sensor, a speed sensor, a gyro sensor, and the like. The sensor 5 is configured to detect a traveling state of the vehicle 1 and output traveling state information indicating the traveling state of the vehicle 1 to the vehicle control unit 3. The sensor 5 may include an outside air temperature sensor that detects a temperature of air outside the vehicle 1.

The HMI 8 includes an input unit that receives an input operation from a driver and an output unit that outputs traveling information and the like to the driver. The input unit includes a steering wheel, an accelerator pedal, a brake pedal, a driving mode switch for switching a driving mode of the vehicle 1, and the like. The output unit is a display (for example, a head up display (HUD)) that displays various types of traveling information. The GPS 9 is configured to acquire current location information of the vehicle 1 and output the acquired current location information to the vehicle control unit 3.

The wireless communication unit 10 is configured to receive information on other vehicles around the vehicle 1 from the other vehicles and transmit information on the vehicle 1 to the other vehicles (vehicle-to-vehicle communication). The wireless communication unit 10 is configured to receive infrastructure information from an infrastructure facility such as a traffic light or a sign lamp and transmit traveling information of the vehicle 1 to the infrastructure facility (road-to-vehicle communication). The wireless communication unit 10 is configured to receive information on a pedestrian from a portable electronic device (a smart phone, a tablet, a wearable device or the like) carried by the pedestrian and transmit the own vehicle traveling information of the vehicle 1 to the portable electronic device (pedestrian-vehicle communication). The vehicle 1 may directly communicate with the other vehicles, the infrastructure facility or the portable electronic device in an ad-hoc mode, or may perform communication via a communication network such as the Internet.

The storage device 11 is an external storage device such as a hard disk drive (HDD) or a solid state drive (SSD). The storage device 11 may store two-dimensional or three-dimensional map information and/or a vehicle control program. For example, the three-dimensional map information may be configured with 3D mapping data (point group data). The storage device 11 is configured to output the map information and the vehicle control program to the vehicle control unit 3 in response to a request from the vehicle control unit 3. The map information and the vehicle control program may be updated via the wireless communication unit 10 and the communication network.

When the vehicle 1 travels in the automatic driving mode, the vehicle control unit 3 automatically generates at least one of a steering control signal, an accelerator control signal, and a brake control signal based on the traveling state information, the surrounding environment information, the current location information, the map information, and the like. The steering actuator 12 is configured to receive the steering control signal from the vehicle control unit 3 and control the steering device 13 based on the received steering control signal. The brake actuator 14 is configured to receive the brake control signal from the vehicle control unit 3 and control the brake device 15 based on the received brake control signal. The accelerator actuator 16 is configured to receive the accelerator control signal from the vehicle control unit 3 and controls the accelerator device 17 based on the received accelerator control signal. In this way, the vehicle control unit 3 automatically controls traveling of the vehicle 1 based on the traveling state information, the surrounding environment information, the current location information, the map information, and the like. That is, in the automatic driving mode, the traveling of the vehicle 1 is automatically controlled by the vehicle system 2.

On the other hand, when the vehicle 1 travels in the manual driving mode, the vehicle control unit 3 generates the steering control signal, the accelerator control signal, and the brake control signal in accordance with a manual operation of the driver with respect to the accelerator pedal, the brake pedal, and the steering wheel. In this way, in the manual driving mode, since the steering control signal, the accelerator control signal and the brake control signal are generated by the manual operation of the driver, the traveling of the vehicle 1 is controlled by the driver.

Next, the driving mode of the vehicle 1 will be described. The driving mode includes an automatic driving mode and a manual driving mode. The automatic driving mode includes a fully automatic driving mode, an advanced driving support mode, and a driving support mode. In the fully automatic driving mode, the vehicle system 2 automatically performs all kinds of traveling control including steering control, brake control, and accelerator control, and the driver cannot drive the vehicle 1. In the advanced driving support mode, the vehicle system 2 automatically performs all kinds of traveling control including the steering control, the brake control, and the accelerator control, and the driver can drive the vehicle 1 but does not drive the vehicle 1. In the driving support mode, the vehicle system 2 automatically performs a part of traveling control including the steering control, the brake control, and the accelerator control, and the driver drives the vehicle 1 under driving support of the vehicle system 2. On the other hand, in the manual driving mode, the vehicle system 2 does not automatically perform the traveling control, and the driver drives the vehicle 1 without the driving support of the vehicle system 2.

(Description of Dirt Detection Method)

Next, a method of detecting dirt adhering to the outer cover 22 a of the left-front lamp 7 a will be described below with reference to FIG. 4. FIG. 4 is a flowchart for illustrating the method of detecting dirt adhering to the outer cover 22 a (hereinafter, referred to as “dirt detection method”). Although only dirt detection processing executed by the dirt detection system 6 a will be described in the present embodiment, it should be noted that dirt detection processing executed by the dirt detection systems 6 b to 6 d is the same as the dirt detection processing executed by the dirt detection system 6 a.

As illustrated in FIG. 4, in step S1, the vehicle control unit 3 determines whether an object (in particular, a pedestrian) exists outside the vehicle 1 based on surrounding environment information transmitted by the sensing systems 4 a to 4 d. When a determination result of step S1 is YES, the present determination processing is repeatedly executed until the determination result of step S1 is NO. On the other hand, when the determination result of step S1 is NO, the processing proceeds to step S2.

Next, in step S2, the lamp cleaner control unit 64 a activates the thermal imaging camera 62 a. When the thermal imaging camera 62 a is already activated, processing of steps S2 and S3 is skipped. Next, in step S3, the lamp cleaner control unit 64 a acquires thermal image data indicating the outer cover 22 a from the thermal imaging camera 62 a. In particular, the thermal image data may indicate a region of the outer cover 22 a through which the laser light emitted from the LiDAR unit 44 a passes.

Next, in step S4, the lamp cleaner control unit 64 a acquires, from the vehicle control unit 3, information on an outside air temperature of air outside the vehicle 1 acquired by an outside air temperature sensor. Thereafter, the lamp cleaner control unit 64 a determines a threshold temperature corresponding to the outside air temperature. For example, when the outside air temperature is low, the threshold temperature may be set to a low temperature. Conversely, when the outside air temperature is high, the threshold temperature may be set to a high temperature.

Next, the lamp cleaner control unit 64 a determines, based on the thermal image data, whether there is a high-temperature region having a temperature equal to or higher than the threshold temperature (step S5). Here, the thermal image data (thermography) indicates temperature distribution of a captured surrounding environment. Therefore, the lamp cleaner control unit 64 a can detect, from the thermal image data, whether there is a high-temperature region having a temperature equal to or higher than the threshold temperature in the captured outer cover 22 a. When a determination result of step S5 is YES, the processing proceeds to step S6. On the other hand, when the determination result of step S5 is NO, in step S7, the lamp cleaner control unit 64 a determines that there is no dirt adhering to the outer cover 22 a, and then ends the present processing.

Next, in step S6, the lamp cleaner control unit 64 a determines whether the high-temperature region present in the thermal image data covers an area equal to or larger than a predetermined area. When a determination result of step S6 is YES, the lamp cleaner control unit 64 a determines that there is dirt adhering to the outer cover 22 a (step S8). On the other hand, when the determination result of step S6 is NO, the lamp cleaner control unit 64 a determines that there is no dirt adhering to the outer cover 22 a, and then ends the present processing. In step S6, it may be determined whether the high-temperature region is formed of an aggregate of pixels of a predetermined number or more.

Thereafter, in step S9, the lamp cleaner control unit 64 a drives the lamp cleaner 63 a in order to remove the dirt adhering to the outer cover 22 a. Specifically, the lamp cleaner control unit 64 a drives the lamp cleaner 63 a such that a cleaning liquid or air is injected from the lamp cleaner 63 a toward the outer cover 22 a.

After the processing of step S9 is executed, the present processing returns to step S5. In this way, the processing from step S5 to step S9 is repeatedly executed until it is determined that there is no dirt adhering to the outer cover 22 a. Note that the present processing may be terminated after the processing of step S9 is executed.

As described above, according to the present embodiment, it is determined based on the thermal image data whether there is dirt adhering to the outer cover 22 a, and further the outer cover 22 a is driven in response to the determination that there is dirt adhering to the outer cover 22 a. In this way, dirt adhering to the outer cover 22 a can be detected based on the thermal image data acquired from the thermal imaging camera 62 a. In this regard, since dirt such as mud absorbs the light emitted from the illumination unit 42 a or the laser light emitted from the LiDAR unit 44 a, a surface temperature of the dirt is higher than a surface temperature of the outer cover 22 a. Therefore, when there is dirt adhering to the outer cover 22 a, the high-temperature region can be detected from the thermal image data. As described above, it is possible to detect the dirt adhering to the outer cover 22 a based on the thermal image data.

Therefore, since it is possible to reliably detect the dirt adhering to the outer cover 22 a, it is possible to suppress a decrease in detection accuracy of the LiDAR unit 44 a and the camera 43 a disposed in the space Sa defined by the outer cover 22 a and the housing 24 a.

In addition, in the present embodiment, since the determination processing of step S1 is executed, it is possible to reliably prevent a situation where a pedestrian or the like is indicated in the thermal image data. In this way, it is possible to reliably prevent a situation where a pedestrian or the like that radiates heat is determined as dirt adhering to the outer cover 22 a (that is, erroneous detection of dirt).

Further, in the present embodiment, in the processing of step S4, since the threshold temperature is determined according to the outside air temperature of air outside the vehicle 1, it is possible to reliably prevent a situation where the dirt adhering to the outer cover 22 a is not detected according to the outside air temperature.

Second Embodiment

Hereinafter, a second embodiment of the present disclosure (hereinafter, simply referred to as “the present embodiment”) will be described. In the description of the present embodiment, a description of members having the same reference numerals as those of the members already described in the first embodiment will be omitted for convenience of description. Dimensions of members shown in the drawings may be different from actual dimensions of the members for convenience of description.

Further, in the description of the present embodiment, for convenience of description, a “left-right direction”, a “front-rear direction”, and an “up-down direction” may be referred to as appropriate. These directions are relative directions set for a vehicle 1A illustrated in FIG. 5. Here, the “front-rear direction” is a direction including a “front direction” and a “rear direction”. The “left-right direction” is a direction including a “left direction” and a “right direction”. The “up-down direction” is a direction including an “upward direction” and a “downward direction”. Although the up-down direction is not shown in FIG. 5, the up-down direction is a direction perpendicular to the front-rear direction and the left-right direction.

First, the vehicle 1A and a vehicle system 2A according to the present embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a schematic diagram illustrating a top view of the vehicle 1A that includes the vehicle system 2A. FIG. 6 is a block diagram illustrating the vehicle system 2A.

The vehicle 1A is a vehicle (automobile) that can travel in an automatic driving mode, and as illustrated in FIG. 5, includes the vehicle system 2A, the left-front lamp 7 a, the right-front lamp 7 b, the left-rear lamp 7 c, and the right-rear lamp 7 d.

As illustrated in FIGS. 5 and 6, the vehicle system 2A includes at least the vehicle control unit 3, a left-front sensing system 104 a (hereinafter, simply referred to as a “sensing system 104 a”), a right-front sensing system 104 b (hereinafter, simply referred to as a “sensing system 104 b”), a left-rear sensing system 104 c (hereinafter, simply referred to as a “sensing system 104 c”), and a right-rear sensing system 104 d (hereinafter, simply referred to as a “sensing system 104 d”).

The vehicle system 2A further includes the sensor 5, the HMI 8, the GPS 9, the wireless communication unit 10, and the storage device 11. In addition, the vehicle system 2A includes the steering actuator 12, the steering device 13, the brake actuator 14, the brake device 15, the accelerator actuator 16, and the accelerator device 17.

The vehicle control unit 3 is configured to control traveling of the vehicle 1A. The vehicle control unit 3, for example, is configured with at least one electronic control unit (ECU).

Each of the sensing systems 104 a to 104 d is configured to detect a surrounding environment of the vehicle 1A. In the description of the present embodiment, it is assumed that the sensing systems 104 a to 104 d include the same components. Therefore, the sensing system 104 a will be described below with reference to FIG. 7. FIG. 7 is a block diagram illustrating the sensing system 104 a.

As illustrated in FIG. 7, the sensing system 104 a includes a control unit 140 a, an illumination unit 142 a, a camera 143 a, a LiDAR unit 44 a (an example of a laser radar), a millimeter wave radar 145 a, and a lamp cleaner 146 a. The control unit 140 a, the illumination unit 142 a, the camera 143 a, the LiDAR unit 144 a, and the millimeter wave radar 145 a are provided in the space Sa defined by the housing 24 a of the left-front lamp 7 a and the translucent outer cover 22 a that are illustrated in FIG. 5. Meanwhile, the lamp cleaner 146 a is disposed outside the space Sa and in the vicinity of the left-front lamp 7 a. Alternatively, the control unit 140 a may be disposed at a predetermined portion of the vehicle 1A other than the space Sa. For example, the control unit 140 a may be configured integrally with the vehicle control unit 3.

The control unit 140 a is configured to control operations of the illumination unit 142 a, the camera 143 a, the LiDAR unit 144 a, the millimeter wave radar 145 a, and the lamp cleaner 146 a. In this regard, the control unit 140 a functions as an illumination unit control unit 520 a, a camera control unit 530 a, a LiDAR unit control unit 540 a, a millimeter wave radar control unit 550 a, and a lamp cleaner control unit 560 a.

The control unit 140 a is configured with at least one electronic control unit (ECU). The electronic control unit includes a computer system (for example, a SoC) including one or more processors and one or more memories, and an electronic circuit including an active element such as a transistor and a passive element. The processor includes at least one of a CPU, an MPU, a GPU and a TPU. The memory includes a ROM and a RAM. Further, the computer system may be configured with a non-von Neumann computer such as an ASIC or an FPGA.

The illumination unit 142 a is configured to emit light toward an outside (a front side) of the vehicle 1A to form a light distribution pattern. The illumination unit 142 a includes a light source that emits light and an optical system. The light source may be configured with, for example, a plurality of light emitting elements arranged in a matrix (for example, N rows×M columns, N>1 and M>1). The light emitting element is, for example, an LED, an LD, or an organic EL element. The optical system may include at least one of a reflector configured to reflect light emitted from the light source toward a front side of the illumination unit 142 a, and a lens configured to refract light directly emitted from the light source or light reflected by the reflector.

The illumination unit control unit 520 a is configured to control the illumination unit 142 a such that the illumination unit 142 a emits light of a predetermined light distribution pattern toward a front region of the vehicle 1A. For example, the illumination unit control unit 520 a may change the light distribution pattern of light emitted from the illumination unit 142 a according to a driving mode of the vehicle 1A.

The camera 143 a is configured to detect a surrounding environment of the vehicle 1A. In particular, the camera 143 a is configured to acquire image data indicating the surrounding environment of the vehicle 1A and then transmit the image data to the camera control unit 530 a. The camera control unit 530 a may specify surrounding environment information based on the transmitted image data. Here, the surrounding environment information may include information on an object that exists outside the vehicle 1A. For example, the surrounding environment information may include information on an attribute of the object existing outside the vehicle 1A and information on a distance, a direction and/or a position of the object with respect to the vehicle 1A. The camera 143 a includes, for example, an imaging element such as a CCD or a CMOS (for example, complementary MOS). The camera 143 a may be configured as a monocular camera or a stereo camera. When the camera 143 a is a stereo camera, the control unit 140 a can specify, by using the parallax, a distance between the vehicle 1A and an object (for example, a pedestrian) existing outside the vehicle 1A based on two or more pieces of image data acquired by the stereo camera.

The LiDAR unit 144 a is configured to detect a surrounding environment of the vehicle 1A. In particular, the LiDAR unit 144 a is configured to acquire point group data indicating the surrounding environment of the vehicle 1A and then transmit the point group data to the LiDAR unit control unit 540 a. The LiDAR unit control unit 540 a may specify the surrounding environment information based on the transmitted point group data.

In this regard, a configuration of the LiDAR unit 144 a according to the present embodiment will be described below with reference to FIG. 8. As illustrated in FIG. 8, the LiDAR unit 144 a includes a plurality of first light emitting units 75 a, a plurality of first light receiving units 76 a, a plurality of second light emitting units 77 a, a plurality of second light receiving units 78 a, a motor 79 a, and a control unit 70 a.

Each of the plurality of first light emitting units 75 a includes a light emitting element configured to emit first laser light having a first peak wavelength, and an optical member such as a lens. The first peak wavelength is, for example, 905 nm. The light emitting element is, for example, a laser diode that emits infrared laser light having a peak wavelength of 905 nm.

Each of the plurality of first light receiving units 76 a includes a light receiving element configured to receive reflected light of the first laser light reflected by an object outside the vehicle 1A and to photoelectrically convert the reflected light of the first laser light, and an optical member such as a lens. The light receiving element is, for example, a Si photodiode having light receiving sensitivity with respect to light in a wavelength band of 300 nm to 1100 nm. Thus, a detection wavelength range of the first light receiving unit 76 a is 300 nm to 1100 nm.

Each of the plurality of second light emitting units 77 a includes a light emitting element configured to emit second laser light having a second peak wavelength, and an optical member such as a lens. The second peak wavelength is, for example, 1550 nm. The light emitting element is, for example, a laser diode that emits infrared laser light having a peak wavelength of 1550 nm.

Each of the plurality of second light receiving units 78 a includes a light receiving element configured to receive reflected light of the second laser light reflected by dirt (for example, rain, snow, mud, and dust) formed on the outer cover 22 a and to photoelectrically convert the reflected light of the second laser light, an optical member such as a lens, and a wavelength filter. The light receiving element is, for example, an InGaAs photodiode having light receiving sensitivity with respect to light in a wavelength band of 800 nm to 1700 nm. The wavelength filter is configured to block at least light in a wavelength band of 800 nm to 1200 nm. Thus, a detection wavelength range of the second light receiving unit 78 a is 1200 nm to 1700 nm. Therefore, in the present embodiment, the detection wavelength range (300 nm to 1100 nm) of the first light receiving unit 76 a and the detection wavelength range (1200 nm to 1700 nm) of the second light receiving unit 78 a do not overlap each other.

In this way, the first light receiving unit 76 a can detect the first laser light but cannot detect the second laser light. The second light receiving unit 78 a can detect the second laser light but cannot detect the first laser light. Therefore, it is possible to prevent a situation where the first light receiving unit 76 a or the second light receiving unit 78 a detects both the first laser light and the second laser light.

As illustrated in FIG. 9, the LiDAR unit 144 a includes a housing 340 a and a LiDAR unit main body 343 a accommodated in the housing 340 a. The plurality of the first light emitting units 75 a, the first light receiving units 76 a, the second light emitting units 77 a, and the second light receiving units 78 a are accommodated in the LiDAR unit main body 343 a. For example, these light emitting units and the light receiving units may be arranged in a straight line along a rotation axis Ax. In FIG. 9, for convenience of illustration, three first and second light emitting units and first and second light receiving units are illustrated, and the number of light receiving units and light emitting units is not particularly limited. For example, the LiDAR unit 144 a may include eight first and second light emitting units and eight first and second light receiving units.

In addition, the first light emitting units 75 a may be configured to emit the first laser light (light pulse) at a same timing. Further, the first light emitting units 75 a may be configured to emit the first laser light at different vertical angles φ in the vertical direction. In this case, an angular pitch Δφ between the vertical angle φ of the first laser light emitted from one first light emitting unit 75 a and the vertical angle φ of the first laser light emitted from another first light emitting unit 75 a adjacent to the one first light emitting unit 75 a may be set to a predetermined angle.

Further, the first light emitting units 75 a are configured to emit the first laser light at a plurality of horizontal angles θ different in a horizontal direction. For example, an angular range in a water bubble direction may be 100°, and an angular pitch Δθ in the horizontal direction may be 0.2°. In this case, the first light emitting units 75 a are configured to emit the first laser light at an angular pitch of 0.2° in the horizontal direction.

Similarly, the second light emitting units 77 a may be configured to emit the second laser light (light pulse) at a same timing. Further, the second light emitting units 77 a may be configured to emit the second laser light at different vertical angles φ in the vertical direction. In this case, the angular pitch Δφ between the vertical angle φ of the second laser light emitted from one second light emitting unit 77 a and the vertical angle φ of the second laser light emitted from another second light emitting unit 77 a adjacent to the one second light emitting unit 77 a may be set to a predetermined angle.

The second light emitting units 77 a are configured to emit the second laser light at a plurality of horizontal angles θ different in the horizontal direction. For example, an angular range in the horizontal direction may be 100°, and the angular pitch Δθ in the horizontal direction may be 0.2°. In this case, the second light emitting units 77 a are configured to emit the second laser light at an angular pitch of 0.2° in the horizontal direction.

The motor 79 a is configured to rotationally drive the LiDAR unit main body 343 a about the rotation axis Ax. By rotationally driving the LiDAR unit main body 343 a, the first light emitting units 75 a and the second light emitting units 77 a can emit laser light at a plurality of horizontal angles θ different in the horizontal direction. For example, the angular range in the horizontal direction may be 100°, and the angular pitch Δθ in the horizontal direction may be 0.2°. In this case, the first light emitting units 75 a can emit the first laser light at an angular pitch of 0.2° in the horizontal direction. Further, the second light emitting units 77 a can emit the second laser light at an angular pitch of 0.2° in the horizontal direction.

The control unit 70 a includes a motor control unit 71 a, a light emission control unit 72 a, a first generation unit 73 a, and a second generation unit 74 a. The control unit 70 a is configured with at least one electronic control unit (ECU). The electronic control unit includes a computer system (for example, a SoC) including one or more processors and one or more memories, and an electronic circuit including an active element such as a transistor and a passive element. The processor includes at least one of a CPU, an MPU, a GPU and a TPU. The memory includes a ROM and a RAM. Further, the computer system may be configured with a non-von Neumann computer such as an ASIC or an FPGA.

The motor control unit 71 a is configured to control driving of the motor 79 a. The light emission control unit 72 a is configured to control light emission of each of the plurality of first light emitting units 75 a and the second light emitting units 77 a.

The first generation unit 73 a is configured to receive a signal corresponding to the reflected light of the first laser light that is output from the first light receiving unit 76 a, and to specify a light reception time of the reflected light of the first laser light based on the received signal. In addition, the first generation unit 73 a is configured to specify an emission time of the first laser light based on a signal output from the light emission control unit 72 a.

In addition, the first generation unit 73 a is configured to acquire information on a time of flight (TOF) ΔT1 that is a time difference between the emission time of the first laser light and the light reception time of the reflected light of the first laser light reflected by an object, at each emission angle (horizontal angle θ, vertical angle φ) of the first laser light. Further, the first generation unit 73 a is configured to generate first point group data indicating a distance D between the LiDAR unit 144 a and the object at each emission angle, based on information on the time of flight ΔT1 at each emission angle. The first generation unit 73 a is configured to transmit the generated first point group data to the LiDAR unit control unit 540 a.

The second generation unit 74 a is configured to receive a signal corresponding to the reflected light of the second laser light that is output from the second light receiving unit 78 a, and to specify a light reception time of the reflected light of the second laser light based on the received signal. In addition, the second generation unit 74 a is configured to specify an emission time of the second laser light based on a signal output from the light emission control unit 72 a.

In addition, the second generation unit 74 a is configured to acquire information on a time of flight (TOF) ΔT2 that is a time difference between the emission time of the second laser light and the reception time of the reflected light of the second laser light reflected by an object, at each emission angle (horizontal angle θ, vertical angle φ) of the second laser light. Further, the second generation unit 74 a is configured to generate second point group data indicating a distance D between the LiDAR unit 144 a and the object at each emission angle, based on information on the time of flight ΔT2 at each emission angle. The second generation unit 74 a is configured to transmit the generated second point group data to the LiDAR unit control unit 540 a.

According to the present embodiment, the LiDAR unit 144 a can generate the first point group data associated with the first laser light and the second point group data associated with the second laser light. Thus, it is possible to provide the LiDAR unit 144 a capable of acquiring two different sets of point group data. In this regard, the surrounding environment information of the vehicle 1A can be acquired using the first point group data of the two sets of point group data. On the other hand, it is possible to acquire information (for example, information on dirt adhering to the outer cover 22 a described later) other than the surrounding environment information of the vehicle 1A by using the second point group data of the two sets of point group data.

In the present embodiment, the LiDAR unit 144 a acquires the first and second point group data by mechanically driving and rotating the light emitting unit and the light receiving unit, but the configuration of the LiDAR unit 144 a is not limited thereto. For example, the LiDAR unit 144 a may include an optical deflector with which scanning is performed with the first laser light and the second laser light in the horizontal direction and the vertical direction. The optical deflector is, for example, a micro electro mechanical systems (MEMS) mirror or a polygon mirror. Further, the LiDAR unit 144 a may acquire the first and second point group data by using a phased array method or a flash method.

Next, returning to FIG. 7, the millimeter wave radar 145 a and the lamp cleaner 146 a will be described below. The millimeter wave radar 145 a is configured to detect radar data indicating a surrounding environment of the vehicle 1A. In particular, the millimeter wave radar 145 a is configured to acquire radar data and then transmit the radar data to the millimeter wave radar control unit 550 a. The millimeter wave radar control unit 550 a is configured to acquire surrounding environment information based on the radar data. The surrounding environment information may include information on an object existing outside the vehicle 1A. For example, the surrounding environment information may include information on a position and a direction of the object with respect to the vehicle 1A and information on a relative speed of the object with respect to the vehicle 1A.

For example, the millimeter wave radar 145 a can acquire a distance between the millimeter wave radar 145 a and the object existing outside the vehicle 1A and a direction using a pulse modulation method, a frequency modulated continuous wave (FM-CW) method, or a two-frequency CW method. When the pulse modulation method is used, the millimeter wave radar 145 a can acquire information on the time of flight ΔT2 of a millimeter wave, and then acquire information on a distance D between the millimeter wave radar 145 a and the object existing outside the vehicle 1A based on the information on the time of flight ΔT2. In addition, the millimeter wave radar 145 a can acquire information on the direction of the object with respect to the vehicle 1A based on a phase difference between a phase of the millimeter wave (received wave) received by one reception antenna and a phase of the millimeter wave (received wave) received by another reception antenna adjacent to the one reception antenna. Further, the millimeter wave radar 145 a can acquire information on a relative speed V of the object with respect to the millimeter wave radar 145 a based on a frequency f0 of a transmitted wave emitted from a transmission antenna and a frequency f1 of a received wave received by a reception antenna.

The lamp cleaner 146 a is configured to remove dirt adhering to the outer cover 22 a, and is disposed in the vicinity of the outer cover 22 a (see FIG. 11). The lamp cleaner 146 a may be configured to remove dirt adhering to the outer cover 22 a by injecting a cleaning liquid or air toward the outer cover 22 a.

The lamp cleaner control unit 560 a is configured to control the lamp cleaner 146 a. The lamp cleaner control unit 560 a is configured to determine whether there is dirt (for example, rain, snow, mud and dust) adhering to the outer cover 22 a based on the second point group data transmitted from the LiDAR unit control unit 540 a. Further, the lamp cleaner control unit 560 a is configured to drive the lamp cleaner 146 a in response to a determination that there is dirt adhering to the outer cover 22 a.

Similarly, each of the sensing systems 104 b to 104 d includes a control unit, an illumination unit, a camera, a LiDAR unit, a millimeter wave radar, and a lamp cleaner. In particular, these devices of the sensing system 104 b are disposed in the space Sb defined by the housing 24 b of the right-front lamp 7 b and the translucent outer cover 22 b that are illustrated in FIG. 5. These devices of the sensing system 104 c are disposed in the space Sc defined by the housing 24 c of the left-rear lamp 7 c and the translucent outer cover 22 c. These devices of the sensing system 104 d are disposed in the space Sd defined by the housing 24 d of the right-rear lamp 7 d and the translucent outer cover 22 d.

(Dirt Detection Method According to Present Embodiment)

Next, a method of detecting dirt adhering to the outer cover 22 a of the left-front lamp 7 a will be described below mainly with reference to FIG. 10. FIG. 10 is a flowchart for illustrating the method of detecting dirt adhering to the outer cover 22 a (hereinafter, referred to as “dirt detection method”). Although only dirt detection processing executed by the sensing system 6 a will be described in the present embodiment, it should be noted that dirt detection processing executed by the sensing systems 6 b to 6 d is the same as the dirt detection processing executed by the sensing system 6 a.

As illustrated in FIG. 10, in step S11, in accordance with an instruction from the lamp cleaner control unit 560 a, the LiDAR unit control unit 540 a controls the LiDAR unit 144 a so that second laser light L2 is emitted to the outside from the plurality of second light emitting units 77 a of the LiDAR unit 144 a. Here, the LiDAR unit 144 a emits the second laser light L2 at each emission angle (horizontal angle θ, vertical angle φ). Further, an emission intensity I2 of the second laser light L2 emitted from the second light emitting unit 77 a is smaller than an emission intensity I1 of first laser light L1 emitted from the first light emitting unit 75 a. In this regard, as illustrated in FIG. 11, the emission intensity I1 of the first laser light L1 is set to a magnitude at which reflected light of the first laser light L1 reflected by an object existing outside the vehicle 1A can be detected by the first light receiving unit 76 a. In this regard, a maximum arrival distance of the first laser light L1 is within a range of several tens of meters to several hundreds of meters. On the other hand, the emission intensity I2 of the second laser light L2 is set such that a maximum arrival distance of the second laser light L2 is in the vicinity of the outer cover 22 a. That is, at the emission intensity I2 of the second laser light L2, while reflected light of the second laser light L2 reflected by the object existing outside the vehicle 1A cannot be detected by the second light receiving unit 78 a, reflected light of the second laser light L2 reflected by the outer cover 22 a can be detected by the second light receiving unit 78 a.

Next, in step S12, each of the plurality of second light receiving units 78 a of the LiDAR unit 144 a receives the reflected light of the second laser light L2 reflected by the outer cover 22 a.

Next, in step S13, the second generation unit 74 a acquires information on a time of flight ΔT2 that is a time difference between an emission time of the second laser light L2 and a reception time of the reflected light of the second laser light L2 reflected by the outer cover 22 a, for each emission angle of the second laser light L2. Thereafter, the second generation unit 74 a generates second point group data indicating the distance D between the LiDAR unit 144 a and the outer cover 22 a at each emission angle, based on the information on the time of flight ΔT2 at each emission angle. Thereafter, the generated second point group data is transmitted to the lamp cleaner control unit 560 a via the LiDAR unit control unit 540 a.

Next, in step S14, the lamp cleaner control unit 560 a determines whether there is a point group satisfying a predetermined condition in the second point group data. In this regard, the predetermined condition is a condition associated with dirt adhering to the outer cover 22 a. Here, when there is dirt such as mud adhering to the outer cover 22 a, the reflected light of the second laser light L2 reflected by the dirt is detected by the second light receiving unit 78 a. Therefore, in the second point group data, dirt adhering to the outer cover 22 a is indicated as a point group. On the other hand, since the outer cover 22 a is a translucent cover, when there is no dirt on the outer cover 22 a, there is no point group including a predetermined number of points in the second point group data.

In this way, when there is dirt adhering to the outer cover 22 a, a point group caused by the dirt is indicated in the second point group data. For example, when there is a point group including a predetermined number of points in the second point group data, it is determined that there is a point group associated with dirt in the second point group data.

When a determination result of step S14 is YES, the lamp cleaner control unit 560 a determines that there is dirt adhering to the outer cover 22 a (step S16). On the other hand, when the determination result of step S14 is NO, the lamp cleaner control unit 560 a determines that there is no dirt adhering to the outer cover 22 a (step S15).

Thereafter, in step S17, the lamp cleaner control unit 560 a drives the lamp cleaner 146 a in order to remove the dirt adhering to the outer cover 22 a. Specifically, the lamp cleaner control unit 560 a drives the lamp cleaner 146 a such that a cleaning liquid or air is injected from the lamp cleaner 146 a toward the outer cover 22 a.

After the lamp cleaner 146 a performs dirt removing processing on the outer cover 22 a (after the processing of step S17 is performed), the present processing returns to step S11. In this way, the processing from step S11 to step S17 is repeatedly executed until it is determined that there is no dirt adhering to the outer cover 22 a. The present processing may be terminated after the processing of step S17 is executed.

As described above, according to the present embodiment, it is determined based on the second point group data whether there is dirt adhering to the outer cover 22 a, and further the lamp cleaner 146 a is driven in response to the determination that there is dirt adhering to the outer cover 22 a. Thus, it is possible to detect the dirt adhering to the outer cover 22 a based on the second point group data of one of the two sets of point group data acquired from the LiDAR unit 144 a. In this regard, when dirt such as rain, snow, dust, or mud adheres to the outer cover, a point group indicating the dirt adhering to the outer cover 22 a appears in the second point group data, and thus it is possible to detect the dirt adhering to the outer cover 22 a based on the point group. Accordingly, since the dirt adhering to the outer cover 22 a can be detected with high accuracy, it is possible to suppress a decrease in detection accuracy of a sensor such as the LiDAR unit 144 a disposed in the left-front lamp 7 a.

In addition, according to the present embodiment, since the emission intensity I2 of the second laser light L2 is small, the second point group data indicates a surrounding environment within a predetermined distance from the LiDAR unit 144 a. Specifically, the second point group data indicates the outer cover 22 a that exists within the predetermined distance from the LiDAR unit 144 a. In this way, since a point group indicating an object existing outside the vehicle 1A does not appear in the second point group data, it is possible to determine whether there is dirt adhering to the outer cover 22 a based on presence or absence of a point group appearing in the second point group data.

In the present embodiment, the emission intensity I2 of the second laser light is set such that the maximum arrival distance of the second laser light L2 is in the vicinity of the outer cover 22 a, but the present embodiment is not limited thereto. For example, the emission intensity I2 of the second laser light may be equal to or greater than the emission intensity I1 of the first laser light. In this case, similarly to the first point group data, an object outside the vehicle 1A is specified according to the second point group data. Alternatively, in the processing of step S14, the lamp cleaner control unit 560 a may determine whether there is a point group, in the second point group data, satisfying a predetermined condition within a predetermined distance from the LiDAR unit 144 a. Here, it is assumed that the outer cover 22 a is disposed within the predetermined distance from the LiDAR unit 144 a. When it is determined that there is a point group satisfying the predetermined condition within the predetermined distance from the LiDAR unit 144 a, the lamp cleaner control unit 560 a may determine that there is dirt adhering to the outer cover 22 a. On the other hand, when it is determined that there is no point group satisfying the predetermined condition within the predetermined distance from the LiDAR unit 144 a, the lamp cleaner control unit 560 a may determine that there is no dirt adhering to the outer cover 22 a. In this way, even when the second point group data indicates a surrounding environment outside the vehicle 1A, it is possible to determine whether there is dirt adhering to the outer cover 22 a.

Although the embodiments of the present invention have been described, it is needless to say that the technical scope of the present invention should not be interpreted as being limited by the description of the present embodiments. It is to be understood by those skilled in the art that the present embodiments are merely examples and various modifications may be made within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and an equivalent scope thereof.

The present application appropriately incorporates the contents disclosed in Japanese Patent Application No. 2019-026549 filed on Feb. 18, 2019 and the contents disclosed in Japanese Patent Application No. 2019-026550 filed on Feb. 18, 2019. 

1. A dirt detection system for detecting dirt adhering to an outer cover of a vehicle lamp equipped with a sensor for detecting a surrounding environment of a vehicle, the dirt detection system comprising: a thermal imaging camera configured to acquire thermal image data indicating the outer cover; a lamp cleaner configured to remove dirt adhering to the outer cover; and a lamp cleaner control unit configured to determine based on the thermal image data whether there is dirt adhering to the outer cover, and to drive the lamp cleaner in response to a determination that there is dirt adhering to the outer cover.
 2. The dirt detection system according to claim 1, wherein the thermal imaging camera is disposed in a space defined by a housing and the outer cover of the vehicle lamp.
 3. The dirt detection system according to claim 1, wherein the lamp cleaner control unit is configured to determine based on the thermal image data whether there is dirt adhering to the outer cover when there is no pedestrian present within a predetermined range from the vehicle.
 4. The dirt detection system according to claim 1, wherein the lamp cleaner control unit is configured to specify a high-temperature region having a temperature equal to or higher than a threshold temperature based on the thermal image data, determine whether the specified high-temperature region covers an area equal to or larger than a predetermined area, and determine that there is dirt adhering to the outer cover when the high-temperature region covers an area equal to or larger than the predetermined area.
 5. The dirt detection system according to claim 4, wherein the lamp cleaner control unit is configured to determine the threshold temperature according to an outside air temperature outside the vehicle.
 6. A vehicle comprising the dirt detection system according claim
 1. 7. A LiDAR unit, comprising: a first light emitting unit configured to emit first laser light having a first peak wavelength; a first light receiving unit configured to receive reflected light of the first laser light and to photoelectrically convert the reflected light of the first laser light; a second light emitting unit configured to emit second laser light having a second peak wavelength different from the first peak wavelength; a second light receiving unit configured to receive reflected light of the second laser light and to photoelectrically convert the reflected light of the second laser light; a first generation unit configured to generate first point group data based on an emission time of the first laser light and a light reception time of the reflected light of the first laser light; and a second generation unit configured to generate second point group data based on an emission time of the second laser light and a light reception time of the reflected light of the second laser light, wherein a detection wavelength range of the first light receiving unit and a detection wavelength range of the second light receiving unit do not overlap each other.
 8. The LiDAR unit according to claim 7, wherein an emission intensity of the second laser light is smaller than an emission intensity of the first laser light.
 9. A sensing system for a vehicle configured to detect dirt adhering to an outer cover of a vehicle lamp provided in a vehicle, the sensing system for a vehicle comprising: the LiDAR unit according to claim 7 disposed in a space defined by a housing and the outer cover of the vehicle lamp, and configured to acquire first point group data and second point group data indicating a surrounding environment outside the vehicle; a lamp cleaner configured to remove dirt adhering to the outer cover; and a lamp cleaner control unit configured to determine whether there is dirt adhering to the outer cover based on the second point group data, and to drive the lamp cleaner in response to a determination that there is dirt adhering to the outer cover.
 10. The sensing system for a vehicle according to claim 9, wherein the second point group data indicates a surrounding environment within a predetermined distance from the LiDAR unit, and wherein when there is dirt adhering to the outer cover, the lamp cleaner control unit determines, as dirt adhering to the outer cover, a point group that is indicated by the second point group data.
 11. The sensing system for a vehicle according to claim 9, wherein the second point group data indicates a surrounding environment outside the vehicle, and wherein when there is dirt adhering to the outer cover, the lamp cleaner control unit determines, as dirt adhering to the outer cover, a point group that is indicated by the second point group data and that exists within a predetermined distance from the LiDAR unit.
 12. A vehicle comprising the sensing system for a vehicle according claim
 9. 